The present invention relates generally to operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides apparatus and methods for achieving a lateral wellbore connection.
Where it is desired to drill a lateral wellbore from a parent wellbore, it is common practice to position a whipstock in casing lining the parent wellbore, and then mill a window through the casing. The lateral wellbore may then be drilled outward from the parent wellbore by passing drill bits through the window. Unfortunately, these operations are usually very time-consuming and, therefore, very expensive to perform.
It would be advantageous to provide an exit joint made of a drillable material in the parent wellbore casing string, so that the time involved in milling through the casing would be virtually eliminated. For operational efficiency and structural integrity of the lateral wellbore connection, it would be desirable for the exit joint to be configured as a cementing shoe or other portion of a typical casing string.
Since passage of tools, tubular members and other equipment from the parent wellbore to the lateral wellbore generally requires some rotational orientation, it would also be advantageous to provide apparatus which reduces the time required to rotationally orient items of equipment in the well. For example, one deflection device may be used to guide a drill bit to cut through the casing string, and thereafter another deflection device may be used to guide other equipment from the parent wellbore to the lateral wellbore. The second deflection device could be rotationally oriented using the rotational orientation of the first deflection device.
Accordingly, it is an object of the present invention to provide a lateral wellbore connection which does not require time-consuming milling operations, and which does not require repetitive downhole rotational orientation of items of equipment used therein.